*Confirmed*
you can still use the hidden parts
{ Engine stage 4&5 in most but not all cars
Weight Reduction 4&5
Triple-plate Clutch
Racing Flywheel
Racing Catalytic Converter
Ultra High Rpm Turbo
Super High Rpm Turbo }
You can still change the paint color on the amemiya fd3s rx7, aem s2k and most unpaintable cars through hex on bruteforce.
as for suspension and horsepower its a no go, if you make your changes on bruteforce it will not hold when you start the game, all horsepower and suspension reverts to stock. the same goes for any motor swapping.
and if you go overboard with swapping parts on a car the game wont even load, stating that there is no such car.
you better hope to God you made a backup save before messing with your savedata.
hope this info helps you guys :mmm: